As seen in mobile telephones, laptop computers, and the like, miniaturization and sophistication of electronic devices have become more and more notable recently. Along with the miniaturization and sophistication of electronic devices, printed wiring boards, which are mounted in the electronic devices, have also been miniaturized more and more, and thus there is a demand for a high-density mounting technique that mounts electronic components with different sizes in a narrow region of the printed wiring board.
In relation to this, proposed is a technique that mounts electronic components with different sizes in the same position on a flat surface of the printed wiring board. For example, there are known mounting lands of chip components that include an assembly of multiple land portions having widths respectively corresponding to electrode widths of multiple chip components having different chip sizes in which the multiple lands are combined and arranged in the form of T-shaped blocks in the assembly. These techniques are disclosed for example in Japanese Laid-open Patent Publication No. 2003-243814.
As described above, when multiple land portions are arranged by simply combining them in the form of T-shaped blocks, they are formed in such a manner that multiple land portions, on which electronic components having different sizes are to be mounted, are continuously connected. In this case, when solder is heated at the time of mounting the electronic components, electrode portions of the electronic components to be mounted are pulled toward the land portions for mounting the electronic components having different sizes due to the surface tension of the melted solder, which may cause displacement in mounting the electronic components and mounting defects.